Sandstorms mainly form in deserts due to the specific conditions of these regions: intense heat generates upward air movements, while the absence of vegetation and relief promotes the suspension of sand particles by strong winds, creating sandstorms.
In deserts, prevailing winds play a crucial role in triggering sandstorms. Basically, it's simple: powerful and consistent currents arise due to differences in atmospheric pressure, like warm and dry air flows from neighboring regions. As a result, these persistent winds strike directly at the barren desert surface without protective vegetation and easily lift sand particles. Once in the air, the sand becomes a sort of projectile that hits others, quickly amplifying the phenomenon. These prevailing winds then rapidly spread the sand over long distances, creating the famous storms capable of crossing hundreds of kilometers. That's why, in deserts, a few well-placed gusts are enough to turn a quiet afternoon into an apocalyptic movie set.
In the desert, the sand is often very fine, light, and dry. It can thus easily be blown away as soon as the wind picks up a bit. Many desert sand grains are rounded, which makes them less adhesive to each other and very mobile. This low weight and fluidity allow the sand to start moving quickly, even with a weak wind. Once lifted, the sand strikes other grains on the ground, creating a snowball effect (or rather a sandball effect)— it quickly multiplies the grains in suspension. Additionally, in a desert, little humidity binds the grains together, so as soon as a gust arrives, the sand easily takes off to generate impressive storms.
In deserts, the climate is so dry that plants do not really venture there. This lack of vegetation makes the soil vulnerable: no roots to hold the earth, nothing to block the light grains. As a result, with the slightest gust of wind, the sand easily blows away. And the higher the aridity, the drier and finer the soil is, and its surface becomes loose, which makes the sand even more ready to take to the air at the slightest breath. Without plants to slow down the wind, no natural barrier really prevents gusts from gaining strength, often leading to the famous sand clouds that characterize these impressive storms.
In deserts, the climate is extremely hot during the day and very cold at night. These strong temperature variations create frequent and intense air movements. When it's hot, the air at ground level heats up tremendously and rises quickly, causing turbulence. This turbulence then facilitates the lifting of sand at the surface. Additionally, there is often very dry air, which further dries out the ground and makes the sand particles easy to move. As a result, the perfect conditions are in place for sandstorms to start quickly and spread easily.
The shape of the terrain is often crucial in triggering sandstorms. For example, regions with narrow valleys and rocky mountains act like huge funnels, accelerating the wind and facilitating the lift of sand. As a result, these landforms create perfect corridors for the wind to pick up speed. At the same time, the vast flat areas typical of deserts allow the wind to blow over long distances without any obstacles — the result: light sand lifts super easily. The dunes, for their part, also play a major role by constantly providing fine sand ready to take off as soon as the wind picks up a bit.
Some sandstorms from the Sahara are powerful enough to transport sand all the way to the Amazon, bringing essential minerals for the fertility of the soil in this tropical region.
The meteorological phenomenon known as a 'haboob' is an impressive sandstorm that moves like a dense wall reaching several kilometers in height.
NASA regularly studies sandstorms from space, as their movement can influence the global climate and affect air quality up to several thousand kilometers away.
Contrary to popular belief, the sand carried by a sandstorm can sometimes be so fine that it even penetrates inside tightly sealed buildings.
Indeed, sandstorms occur more frequently during transitional seasons such as spring, a time when the winds are often stronger and temperature changes are more pronounced.
Yes, certain regions are particularly affected, such as the Sahara in North Africa, the Arabian deserts in the Middle East, the Gobi Desert in China and Mongolia, as well as some semi-arid regions in the United States and Australia.
Sandstorms can drastically reduce visibility, cause respiratory issues, damage crops, harm vehicle mechanisms, and lead to economic disturbances.
Yes, even if they are rare. They can occur in any region where the soils are dry, devoid of vegetation, and exposed to strong winds, but their occurrence and intensity are much lower than in typical desert environments.
In the event of a sandstorm, it is recommended to avoid going outside, to seal windows and doors tightly, to protect your respiratory passages with a damp cloth, and to wait for the storm to pass in a sheltered place.
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